Hag directly mediates the adherence of Moraxella catarrhalis to human middle ear cells
Hag directly mediates the adherence of Moraxella catarrhalis to human middle ear cells
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DOI：
10.1128/iai.73.8.5127-5136.2005
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发表时间：
2005-08-01
影响因子：
3.1
通讯作者：
Lafontaine, ER
中科院分区：
文献类型：
--
作者：
Bullard, B;Lipski, SL;Lafontaine, ER
卡他莫拉菌是一种人类病原体，会导致幼儿中耳炎和慢性阻塞性肺疾病患者的肺部感染。在这项研究中，检测了表面蛋白HAg在卡他分支杆菌多个菌株的黏附中的作用。用壮观霉素耐药盒阻断4株临床分离株的HAG基因，并测定其与原代培养的人中耳上皮细胞(HMEE)和A549肺泡细胞的结合。这些实验表明，大多数突变体对这两种细胞类型的依附性都比它们的野生型祖细胞少10倍。为了确定HAg是否直接介导对人细胞的黏附，我们克隆了三株卡他分支杆菌的HAg基因，并在非黏附的大肠杆菌克隆株中进行了表达。附着在HMEE细胞上的表达Hag的大肠杆菌至少是粘附阴性对照的17倍。令人惊讶的是，Hag的表达并没有增加重组大肠杆菌与A549单层的结合。我们的数据表明，HAg参与卡他分支杆菌与A549和HMEE细胞的黏附在不同分离株之间是保守的，并且HAg直接介导与HMEE细胞的结合。
Moraxella catarrhalis is a human pathogen that causes otitis media in young children and lung infections in patients with chronic obstructive pulmonary disease. In this study, the role of the surface protein Hag in the adherence of multiple M. catarrhalis strains was examined. The hag genes of four clinical isolates were disrupted with a spectinomycin resistance cassette, and the binding of isogenic mutants to primary cultures of human middle ear epithelial cells (HMEE), as well as A549 pneumocytes, was measured. These experiments revealed that the attachment of most mutants to both cell types was 10-fold less than that of their wild-type progenitors. To determine whether Hag directly mediates adherence to human cells, the hag genes from three M. catarrhalis isolates were cloned and expressed in a nonadherent Escherichia coli cloning strain. At least 17-fold more E. coli bacteria expressing Hag attached to HMEE cells than an adherence-negative control. Surprisingly, Hag expression did not increase the binding of recombinant E. coli to A549 monolayers. Our data demonstrate that the involvement of Hag in M. catarrhalis adherence to A549 and HMEE cells is conserved among isolates and that Hag directly mediates binding to HMEE cells.